Biomedical Engineering Reference
In-Depth Information
Fig. 5 Main modeling
parameters of an AAA
The diseased AAA wall is modeled as a linear, isotropic, elastic material with
a density ¡ D
1.2 g/cm 3 , a Young's Modulus E
D
4.6 MPa and a Poisson's ratio of
0.49 [ 20 ].
The healthy part of the aorta (AAA neck) and iliacs are also modeled as a
linear, isotropic, elastic material with a density ¡ D
1.2 g/cm 3 , a Young's Modulus
E
2 MPa and a Poisson's ratio of 0.45.
The stent-graft model presented uses SHELL elements, and is modeled as a
linear, isotropic material with a Young's Modulus E
D
D
10 MPa and a Poisson's ratio
of 0.3.
The aneurysm sac, an important part of the model for the pressure analysis, is
modeled as a stagnant liquid by using FLUID80 element from the ANSYS element
library. This element allows the simulation of stagnant fluids in containers with no
flow. Figure 6 gives an overview of the meshed mechanical model.
The mechanical domain of the simulation assumes zero displacement at the top
of the AAA neck and at the bottom of the iliacs, while a time dependent uniform
velocity is applied at the inlet of the fluidic domain (Fig. 7 a) and a time dependent
normal traction (due to luminal pressure) on the outlet (Fig. 7 b). The transient
analysis is performed during a full cardiac cycle (1.1 s).
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